First principle study on the Structural and Electronic Properties of Lead-Free Double Halide Perovskite Cs2InSbCl6

The structural and electronic characteristics of Cs2InSbCl6 were investigated using first principle density functional theory (DFT) within local density approximation (LDA) and generalized gradient approximation (GGA) as implemented in the Quantum ESPRESSO package. A supercell with 40 atoms was used in carrying out the calculations, using the optimized lattice parameters of the Cs2InSbCl6 (a = b = c =11.342 Ǻ). The findings revealed that Cs2InSbCl6 is a direct band gap material with gaps of 0.74 eV and 0.99 eV for LDA/PZ and GGA/PBE respectively, in which the GGA/PBE gap shows consistency within the literature range. The calculated densities of states highlight the contributions of the constituent atoms within the valence and the conduction bands.